In Ocean City, there is a food court (a court of tables surrounded by food vendors on the ground floor of 2 story buildings) where they keep the pigeons and seagulls away from landing in the court (or flying too close overhead) with strands of white wire -- relatively heavy gauge since they're clearly visible -- strung across the roof eaves -- maybe every 10 feet or so. I asked and a vendor said it doesn't have to be a net -- they won't fly through even though they could.